This invention relates to apparatus for the manufacture of an elongated tubular film product from a length of flexible flat film by means of a forming collar which folds and shapes the flat flexible film about a cylinder or mandrel.
Applicant's assignee is the owner of U.S. Pat. No. 5,085,036 which is incorporated herewith by reference U.S. Pat. No. 5,085,036 discloses an apparatus for the high speed manufacture of elongated tubular film products from a length of flexible flat film. In that patent, film from a roll is unspooled, passed over a forming collar and thence onto a forming tube. The film on the tube has longitudinal edges that are overlapped and sealed or attached to one another. The film is advanced on the tube by a pair of opposed drive units which are positioned on opposite sides of the forming tube. The advance or drive units transport the film over the tube continuously. The film advance units comprise boggie mounted drive belts positioned on opposite sides of the forming tube. The closed loop belts are designed to frictionally engage the formed film and transfer the film along the tube. In operation these drive units are precisely adjusted to maintain an appropriate spacing between the forming tube and the boggie mounted drive belts. It is important to make sure that the drive belts on each side of the elongate forming tube are uniformly and equally spaced from the forming tube so that the film can be uniformly driven or moved on the tube.
Adjustment of the spacing of the drive units such as the boggie mounted drive belt has required a mounting mechanism which independently positions each boggie mounted drive belts as a desired distance from the center line of the tube. There has remained a need, however, to provide an improved mechanism to simultaneously position the drive or transport assemblies or units on the opposite sides of the cylindrical forming tube. The present invention relates to such a mechanism.